Method of making a combination mold and packaging container



H. J. ELET July 4, 1967 METHOD OF MAKING A COMBINATION MOLD AND PACKAGING CONTAINER 2 Sheets-Sheet l l Filed July l5, 1964 July 4, 1967 H. J. ELET I 3,329,749

METHOD OF MAKING A COMBINATION MOLD AND PACKAGING CONTAINER Filed July 13, 1964 2 sheets-'sheet f NVENTO? www' J, Elst United States Patent Office 3,329,749 Patented July 4, 1967 3 329,749 METHOD OF MAKING A COMBINATION MOLD AND PACKAGING CONTAINER Howard J. Elet, Chicago, Ill., assignor of one-third to Marshall Stein and one-third to Ronald B. Gottsegen, both of Chicago, Ill.

Filed July 13, 1964, Ser. No. 382,289 5 Claims. (Cl. 264-45) This invention -relates to a combination mold and packaging container for molded concrete products and the like and to a method of molding and packaging such products.

The use of decorative cast concrete blocks for wall structures, fencing and as space dividers is well known. Heretofore, such blocks were cast by pouring a concrete mix into peramnent molds, generally made of metal, rubber or plastics. The blocks were allowed to set up in such molds for an interval from twelve to twenty-four hours, after which they were removed and stacked on pallets and bound together by steel strapping for shipment to a point of use.

The prior art method of fabricating such blocks had many disadvantages, foremost of which was the extremely high incidenceof breakage of the cast blocks resulting from handling and shipping because the completed blocks were not properly protected. Past experience in the industry indicated a breakage rate of approximately 25-40 percent. The use of expensive molds was required which necessitated a large capital investment in equipment. Additionally, such molds were required to be tied up for extended periods of time in the fabrication of individual blocks, since each block had to set up in the mold a sufcient length of time in order to acquire adequate structural integrity before it could be removed from the mold.

Accordingly, it is an object of my invention to provide a disposable mold formed of a suitable foamed plastic material or the like which functions both as the casting mold into which concrete is poured to form a block, or structure as well as the packaging container for the iinished block or structure.

Another object of my invention is the provision of an inexpensive disposable mold of the foregoing character which has structural integrity and insulating properties adequate to support and protect la cast block or structure against breakage or injury while in storage or in shipment.

A further object of my invention is the provision of a method of producing cast concrete blocks or structures which effects substantial economies in the manufacture of the same.

Still a further object of this invention is the provision of a method of producing cast concrete blocks or structures which permit casting of relatively complex designs and configurations having undercuts, since the mold is expendable and may be destroyed for the purpose of removing a cast block or structure from the mold.

Other and further -objects and advantages of my invention will be apparent from the following description when the same is considered in connection with the accompanying drawings, in which FIG. 1 is a top plan View of a master pattern and casting box utilized in the process of forming the mold land packaging container of my invention with the cover member broken away and with certain parts broken away to show details; i

FIG. 2 is a cross-sectional view taken substantially on line 2 2 of FIG. 1;

FIG. 3 is a top plan view of a completed mold and packaging container removed from the master pattern and casting box and in an inverted position in relation to FIG. 2;

FIG. 4 is a cross-sectional view taken substantially on line 4 4 of FIG. 3;

FIG. 5 is a top plan view of a completed cast block or structure;

FIG. 6 is a vertical cross-sectional view showing one cast block and packaging container stacked on another and illustrating the complete insulation of the fabricated blocks or structures from each other;

FIG. 7 is a fragemntary perspective view showing a plurality of mold and packaging containers, in accordance with my invention, as they would appear stacked for storage and shipment.

Referring to the drawings, particularly to FIGS. 1 and 2, there is illustrated a master mold 10 comprising a casting box 11 prefer-ably formed of metal and including a bottom member 12 and vertical wall members 13. A pattern 14 corresponding to the core of the mold, may be formed of metal or epoxy resins and is so mounted on the bottom member 12 as to provide a uniform perimetric spacing between the walls of the pattern 14 and corresponding wall members 13 of the casting box. A closure member 15 overlies the casting box 11. It will be understood that the design style and size of the pattern is merely exemplary and that my invention is not to be construed as limited to the design style or size illustrated.

In carrying out the method of my invention I introduce into the master mold 10 a suitable material, either in liquid or solid form, which in combination with other suitable activating agents or with heat or both will initiate a reaction to generate in situ a foamed mass filling all of the voids of the master mold and having a desired structural integrity. I have found, for example, that polystyrene in pellet form when activated by a suitable hydrocarbon agent produces a lightweight foamed product of desirable structural integrity and having a generally impervious skin which is waterproof. It will be understood that my invention is not to be limited to the speciiic foaming material above noted, but that any one of several products available on the market may be utilized for producing the mold of my invention, polyurethane, for example, being another of such materials in this class.

The foamed plastic product produced by the master mold and which for convenience I will term a secondary mold 16, -actually .is a negative of the master mold 10 and is itself provided with a base 17 and vertical walls 18 which constitute a casting box. The cavities in the secondary mold 16, of course, correspond to the physical configunation of the master pattern 14 which is identical to the completed block illustrated in FIG. 5. Both the bottom and vertical Walls of t-he secondary molds have adequate thickness, preferably of the order of one inch, to afford the necessary structural Irigidity to contain and support the concrete when it is poured into the mold, and thereafter to protect the block against injury in storage or transit.

The seconda-ry mold 16 of my invention may be fabricated on conventional commercial plastic molding machines at a relatively high rate of production. Accordingly,

such molds may be economically produced at relatively low cost.

Prior to pouring the concrete mix into the secondary mold 16, the 'ulterior surfaces of each mold prefe-rably are treated or sprayed with a suitable silicone releasing agent to facilitate removal of a cast block 20 from the mold after curing. A concrete mix in a semi-plastic state is poured into the mold 16 and the mold is permitted to remain undisturbed for a short interval `of time until the concrete mix has acquired an initial setting-up, indicating the beginning of lthe curing process. Thereafter, the uncured concrete blocks while yet within the molds 16 may be stacked in a warehouse or other storage facility while awaiting shipment to a point of use. It will be understood that the curing process takes place within the mold 16 during the storage interval and may even continue during shipment. I have found that with the use of my secondary mold the setting-up of the concrete is accelerated so that the cast block in its package container is in condition to be moved to a storage facility at least several hours earlier, after the pouring of the concrete in the mold, than corresponding blocks made according to prior art methods.

The skin which forms the inner surface of the secondary mold 16 is waterproof and accordingly, the moisture content of the concrete is not extracted 'by absorption into the mold, but rather is released slowly to the top surface of the concrete permitting the same to cure properly. The cured block 20 remains within the mold 16 which now serves as a package container during storage and in transit, with the block being completely protected and insulated against any injury. The block 20 may be removed from the mold 16 just prior to its installation at a point of use.

The surface texture of the finished block may be controlled by employing different combinations of ingredients in the mix and/ or using different releasingagents. According to prior art practices the molds themselves would lbe required to be fabricated so as to produce the textured surface in the finished product. It will be understood that the use of a releasing agent may be eliminated if desired, so as to leave a surface on the blocks which is better adapted to accept paint or a surface coating.

It will be noted that my invention affords additional advantages beyond those hereinabove discussed. For example, the master mold which is formed of metal is employed only for the fabrication of the foamed plastic `secondary molds 16 and, accordingly, the metal mold is not subjected to any abrasive action of the concrete, as would be the case according to prior art practicesI where metal molds are employed in the casting of concrete blocks. It will be apparent that abrasive action on a metal mold will result in a gradual erosion of the mold design. This is particularly true in cases where the mold embodies a relatively intricate design. Progressive wear of the mold tends gradually to obliterate the design requiring replacement of the mold after a relatively short service life. In the present invention a mold 16 is employed only once for the fabrication of a single block. Hence, all of the molds of a particular design employed for casting the concrete blocks are identical with the result that the completed cast blocks are of uniform quality and design.

Further, after the secondary molds 16 are fabricated it is not required that the actual casting of the blocks be effected at any particular location. According to prior art practices Where costly -metal molds are employed, the blocks are fabricated at a central point where the molds are located and then the nished blocks are shipped from that point to points of distribution or use. It should be apparent that because of the weight of the completed concrete block-s the shipping charges would be extremely high. On the other hand, with my invention, the secondary molds 16 may be shipped Very economically to a point Y of use where the casting of the concrete blocks may be completed. Because the density of the foamed plastic utilized in the production of the molds 16 is only about one and one-half pounds per cubic foot, a mold for casting a block having conventional dimensions of lr6" X 16" x 4 weighs only la few ounces. A completed cast `block of such dimensions could `Weigh as much as 42 pounds.

It will `be understood that suitable metal members may be positioned in the mold so as to be embedded in the concrete and reinforce the same.

The fact that the mold of my invention is disposable or expendable in character allows the elimination of draft or relief in the mold, which would otherwise be required to facilitate removal or separation of the cast block from the mold. Accordingly, the appearance of the cast product is superior to that of prior art blocks, since intersecting plane surfaces may be disposed exactly at right angles to each other. Such a condition also facilitates installation because a mason or bricklayer need not compensate for the angular relation of the surfaces resulting from the provision of the draft or relief.

The use of a mold of -my invention avoids a time con. suming operation, that of cleaning the mold after each use, as is required in prior art practices. Cleaning of the molds is particularly critical in cases where the concrete is pigmented and limited production runs of different single colors are made using the same molds. The mol-ds according to prior art practices must Ibe thoroughly cleaned after each run in order to avoid contamination of colors. In the practice of my invention a clean mold is always available for immediate use, since the molds are not intended for re-use.

I have found that the insulating properties lof the mold have a beneficial effect on the curing of the cast concrete since crazing of the concrete surfaces is substantially eliminated, resulting in a product of improved quality.

' Further such insulating properties serve to retain the heat generated during curing of the concrete with the result that a cast block Within a mold may be stored in freezing temperatures without deleteriously affecting the curing of the concrete or the finished block. While generally rigid the walls of the mold afford some degree of flexibility to accommodate any expansion of the concrete during curing.

Various changes coming within the spirit of my invention may suggest themselves to those skilled in the art; hence, I do not wish to `be limited to the specific embodiments shown and described or `uses mentioned, but intend the same to be merely exemplary, the scope of my invention being limited only by the appended claims.

I claim:

1. The method of fabricating, packaging and transporting moldable hardened cement composition structures comprising the steps of (a) providing a positive master mold having a cavity,

(b) casting a firm but yieldable foamed plastic material having structural integrity around said master mold to form a negative or secondary mold thereof including the cavity following the removal of the master mold from the cast material,

(c) casting a fiuid cement composition in said negative mold of foamed plastic material to duplicate in said composition said master mold With the cavity therein, and

(d) curing said cast structure while the same remains in said negative mold, preparatory to the transportation of said cast structure in said negative mold and the eventual separation of said structure therefrom.

2. The method set forth in claim 1 wherein the casting of the negative mold is executed in situ yby means of an expandable organic resin in conjunction with an expanding agent therefor.

3. The method set forth in claim 1 wherein the foamed plastic material has a continuous surface skin impervious to moisture.

4. The method set forth in claim 1 wherein said moldable plastic cement composition is concrete.

5 5. The method set forth in claim 3 wherein the curing step is executed While the cast cement composition structure remains in the negative mold in the course of storage and/ 01' transport thereof.

References Cited UNITED STATES PATENTS Daniel 264-220y XR Ford et a1. 249-148 XR Aisenberg 264-313 Cizek 18-47 Buonaiuto 264-53 XR ALEXANDER H. BRODMERKEL, Primary Examiner.

2,402,528 6/1946 Bean 264-225 XR ROBERT 1::` WHITE Exammer 2,611,170 9/1952 Theis 25 2,714,226 8/ 1955 Axelrad 264-337 10 B. SNYDER, A. KOECKERT, Assistant Examiners. 

1. THE METHOD OF FABRICATING, PACKAGING AND TRANSPORTING MODABLE HARDENED CEMENT COMPOSITION STRUCTURES COMPRISING THE STEPS OF (A) PROVIDING A POSITIVE MASTER MOLD HVING A CAVITY, (B) CASTING A FIRM BUT YIELDABLE FOAMED PLASTIC MATERIAL HAVING STRUCTURAL INTEGRITY AROUND SAID MASTER MOLD TO FORM A NEGATIVE OR SECONDARY MOLD THEREOF INCLUDING THE CAVITY FOLLOWING THE REMOVAL OF THE MASTER MOLD FROM THE CAST MATERIAL, (C) CASTING A FLUID CEMENT COMPOSITION IN SAID NEGATIVE MOLD OF FOAMED PLASTIC MATERIAL TO DUPLICATE IN SAID COMPOSITION SAID MASTER MOLD WITH THE CAVITY THEREIN, AND (D) CURING SAID CAST STRUCTURE WHILE THE SAME REMAINS IN SAID NEGATIVE MOLD, PREPARATORY TO THE TRANSPORTATION OF SAID CAST STRUCTURE IN SAID NEGATIVE MOLD AND THE EVENTUAL SEPARATION OF SAID STRUCTURE THEREFROM. 